Liu, Yikui; Li, Jie; Wu, Lei: 'ACOPF for three-phase four-conductor distribution systems: semidefinite programming based relaxation with variable reduction and feasible solution recovery', IET Generation, Transmission & Distribution, 2019, 13, (2), p. 266-276, DOI: 10.1049/iet-gtd.2018.5033
IET Digital Library, https://digital-library.theiet.org/;jsessionid=1i01vtlr6vtc1.x-iet-live-01content/journals/10.1049/iet-gtd.2018.5033